Gas barrier properties refer to the ability of materials to prevent the ingress or egress of gases from a structure. Well known examples of common barrier materials are, for instance, glass bottles and aluminum cans meant to contain food or beverages. The function of the barrier material, besides containing the product, is to prevent the ingress of oxygen which would lead to food spoilage. Additionally, these barrier materials prevent the egress of gases from the container which would lead to product degradation or taste and feel issues for the consumer. For instance, in the case of beverages, the egress of CO2 is limited by the use of proper barrier materials, therefore it is possible to maintain carbonation in beverages.
Rigid materials are often used when barrier properties are desired. However, when weight constraints are an issue, flexible thin thermoplastic films and relatively brittle metal foils can be utilized, as is well known in the art. Well known examples of flexible films or foil composite structures used as barrier materials are that of foil laminations made to produce retortable pouches. The function of the foil is to prevent the ingress of oxygen into the package and prevent food spoilage issues. Thus in a flexible package, aluminum foil is serving the same essential barrier function as that of glass or steel in traditional can and bottle packaging structures.
In the case of lighter than air products, such as, for instance, balloons, promotional items, toys, and the like, the use of rigid materials like glass and steel and metal foils is not practical due to weight issues and cost considerations. Therefore, it is well known in the art to utilize metallized thermoplastic films, including, for example, metallized nylon films or metallized PET (polyethyleneterephthalate) films to serve as the barrier material. However, such thin films are known to have stress cracking issues related to the metal barrier surfaces that often result in increased permeation of lighter than air gases like helium, the gas typically used for inflating the materials. Therefore, the use of traditional metallized nylon and PET films in the construction of lighter than air structures has been for the production of materials with a limited lifetime after inflation with the low density gas.
Therefore, there is a need for the cost effective utilization of thermoplastic films with decreased permeation rates to function as long life barrier materials in the construction of lighter than air products.
U.S. Pat. No. 4,077,588, the disclosure of which is totally incorporated by reference herein, describes in the Abstract thereof a substantially permanently buoyant balloon suitable for use as a toy or in advertising. For example, a balloon is provided which includes an envelope containing a lighter than air gas such as helium. The envelope is made from attached panels of a non-elastomeric polymer sheet material carrying a continuous metal layer on at least one side thereof. The metal layer can either be a thin metal film contiguously bonded to the polymer, or can be metal which is vapor deposited over the surface of the polymer. The balloon itself is constructed so that the ratio of its volume taken to the two-thirds power divided by its surface area is in the range of form about 0.21 to about 0.01, and the weight of the envelope can range form about 2.6×10−4 gm/cm2 to about 1.7×10−2 gm/cm2. The envelope is preferably manufactured in a two dimensional “lay-flat” form in any desired two dimensional shape unlike conventional balloon envelopes which are inherently three dimensional surfaces. Balloon envelopes having the above described volume to surface area ratio and made with the above described composite panel material will be maintained buoyant for an indefinite period of time when filled with the lighter than air gas.
U.S. Pat. No. 5,338,243, the disclosure of which is totally incorporated by reference herein, describes in the Abstract thereof a balloon product, including at least two sheets, having a background depiction on one sheet and a foreground depiction on the other. The foreground depiction has a complementary relationship to the background depiction so as to provide a three-dimensional animated image.
U.S. Pat. No. 5,713,777, the disclosure of which is totally incorporated by reference herein, describes in the Abstract thereof a non-latex inflatable toy in the form of a hand puppet. The puppet includes three sheets defining an inflatable chamber and a pocket for the hand of the user.
U.S. Pat. No. 5,882,747, the disclosure of which is totally incorporated by reference herein, describes in the Abstract thereof a lighter than air balloon constructed from a flexible film material which has coated one or more of its interior or exterior surfaces thereon a barrier material which is not a pure metal and which has an oxygen transmission rate of less than 0.5 cm3/100 in2/24 hr. at 75° F., 65% relative humidity, said balloon being able to float when inflated with a lighter than air gas and a process for producing the balloon is provided. Further of interest include U.S. Pat. Nos. 4,290,763; 4,778,431; 4,917,646; and 5,108,339; the disclosures of each of which are totally incorporated by reference herein.
The appropriate components and process aspects of the each of the foregoing U.S. Patents may be selected for the present disclosure in embodiments thereof.